Manufacturers of printed circuit boards continuously seek ways to prevent corrosion of the copper used in printed circuit boards. This task is made more difficult by the fact that copper is purposely oxidized during the manufacturing process to increase the bonding strength between the copper and the base polymeric material of the printed circuit board. Oxidized copper is more readily corroded by acid than elemental copper. Therefore, the manufacturing process increases the possibility of corrosion. Although the majority of these copper oxide surfaces are covered with resin and thus protected from contact with acid, some exposed copper oxide surfaces remain. For example, exposed copper oxide surfaces are typically found at the edges of the printed circuit board or the through-holes used to interconnect the layers in multi-layer boards.